Germline mutations in the ribonuclease L gene in families showing linkage with HPC1.

Although prostate cancer is the most common non-cutaneous malignancy diagnosed in men in the United States, little is known about inherited factors that influence its genetic predisposition. Here we report that germline mutations in the gene encoding 2'-5'-oligoadenylate(2-5A)-dependent RNase L (RNASEL) segregate in prostate cancer families that show linkage to the HPC1 (hereditary prostate cancer 1) region at 1q24-25 (ref. 9). We identified RNASEL by a positional cloning/candidate gene method, and show that a nonsense mutation and a mutation in an initiation codon of RNASEL segregate independently in two HPC1-linked families. Inactive RNASEL alleles are present at a low frequency in the general population. RNASEL regulates cell proliferation and apoptosis through the interferon-regulated 2-5A pathway and has been suggested to be a candidate tumor suppressor gene. We found that microdissected tumors with a germline mutation showed loss of heterozygosity and loss of RNase L protein, and that RNASEL activity was reduced in lymphoblasts from heterozyogous individuals compared with family members who were homozygous with respect to the wildtype allele. Thus, germline mutations in RNASEL may be of diagnostic value, and the 2-5A pathway might provide opportunities for developing therapies for those with prostate cancer.

Evidence for a prostate cancer susceptibility locus on the X chromosome.

Over 200,000 new prostate cancer cases are diagnosed in the United States each year, accounting for more than 35% of all cancer cases affecting men, and resulting in 40,000 deaths annually. Attempts to characterize genes predisposing to prostate cancer have been hampered by a high phenocopy rate, the late age of onset of the disease and, in the absence of distinguishing clinical features, the inability to stratify patients into subgroups relative to suspected genetic locus heterogeneity. We previously performed a genome-wide search for hereditary prostate cancer (HPC) genes, finding evidence of a prostate cancer susceptibility locus on chromosome 1 (termed HPC1; ref. 2). Here we present evidence for the location of a second prostate cancer susceptibility gene, which by heterogeneity estimates accounts for approximately 16% of HPC cases. This HPC locus resides on the X chromosome (Xq27-28), a finding consistent with results of previous population-based studies suggesting an X-linked mode of HPC inheritance. Linkage to Xq27-28 was observed in a combined study population of 360 prostate cancer families collected at four independent sites in North America, Finland and Sweden. A maximum two-point lod score of 4.60 was observed at DXS1113, theta=0.26, in the combined data set. Parametric multipoint and non-parametric analyses provided results consistent with the two-point analysis. Significant evidence for genetic locus heterogeneity was observed, with similar estimates of the proportion of linked families in each separate family collection. Genetic mapping of the locus represents an important initial step in the identification of an X-linked gene implicated in the aetiology of HPC.

Dietary supplement use patterns in men with prostate cancer: the Cancer Prostate Sweden study.

BACKGROUND: In a European setting, we know little about the use of dietary supplements among men with prostate cancer (PCa) and to what extent lifestyle, disease or other factors influence such use. PATIENTS AND METHODS: We evaluated supplement use in 1127 men with incident PCa and in 900 population controls in Sweden. Age-adjusted binary regression with an identity link was carried out to estimate prevalence differences and corresponding 95% confidence intervals (CIs). Modifying effects of lifestyle- and diet-related factors were explored by statistical assessment of additive interaction. RESULTS: Among men with PCa, 542 individuals (48%) had used supplements, which was a 10% (95% CI: 5.9%-15%) higher prevalence than among population controls. Among individuals with high intake of fatty fish, vegetables, and phytoestrogens, but low intake of saturated fat, supplement use was 29% (95% CI: 18%-41%) more common in men with PCa than in population controls. We found no evidence of heterogeneity by categories of education, smoking history, body mass index, fiber, fruit, or phytoestrogen intake, treatment, or disease stage. CONCLUSION: Supplement use is common in Swedish men with PCa, especially among those with a healthy dietary pattern.

Serum calcium and the risk of prostate cancer.

BACKGROUND: Recent studies have suggested an association between high dietary intake of calcium and the risk of prostate cancer. Calcium-rich diet has been suggested to affect the serum levels of Vitamin D, and thereby promote cancer. We conducted the largest study of the association between prediagnostic serum levels of calcium and the risk of prostate cancer. OUTLINE: We examined the incidence of prostate cancer in relation to prediagnostic serum calcium levels in a prospective cohort study of 22,391 healthy Swedish men, of which 1,539 incident cases of prostate cancer were diagnosed during the 30 years of follow-up until December 2006. MATERIAL AND METHODS: Serum levels of calcium were measured at baseline, and categorized into quartiles. Cox regression was used to estimate the adjusted hazard ratios (HR) with 95% confidence intervals (CI). RESULTS: We found no evidence of an association between prediagnostic serum levels of calcium and risk of prostate cancer (HR for trend = 0.99 [95% CI;0.94-1.03]). However, a moderate significant negative association was seen in men with a BMI above 25 and aged below 45 years at baseline (Highest vs. lowest quartile, HR = 0.63 [95% CI;0.40-0.99]). CONCLUSION: These data do not support the hypothesis that high serum calcium levels is a risk factor for prostate cancer. On the contrary, the data suggest that high serum levels of calcium in young overweight men may be a marker for a decreased risk of developing prostate cancer.

Major susceptibility locus for prostate cancer on chromosome 1 suggested by a genome-wide search.

Despite its high prevalence, very little is known regarding genetic predisposition to prostate cancer. A genome-wide scan performed in 66 high-risk prostate cancer families has provided evidence of linkage to the long arm of chromosome 1 (1q24-25). Analysis of an additional set of 25 North American and Swedish families with markers in this region resulted in significant evidence of linkage in the combined set of 91 families. The data provide strong evidence of a major prostate cancer susceptibility locus on chromosome 1.

Germline variants in IL4, MGMT and AKT1 are associated with prostate cancer-specific mortality: An analysis of 12,082 prostate cancer cases.

BACKGROUND: Prostate cancer (PCa) is a leading cause of mortality and genetic factors can influence tumour aggressiveness. Several germline variants have been associated with PCa-specific mortality (PCSM), but further replication evidence is needed. METHODS: Twenty-two previously identified PCSM-associated genetic variants were genotyped in seven PCa cohorts (12,082 patients; 1544 PCa deaths). For each cohort, Cox proportional hazards models were used to calculate hazard ratios and 95% confidence intervals for risk of PCSM associated with each variant. Data were then combined using a meta-analysis approach. RESULTS: Fifteen SNPs were associated with PCSM in at least one of the seven cohorts. In the meta-analysis, after adjustment for clinicopathological factors, variants in the MGMT (rs2308327; HR 0.90; p-value = 3.5 × 10-2) and IL4 (rs2070874; HR 1.22; p-value = 1.1 × 10-3) genes were confirmed to be associated with risk of PCSM. In analyses limited to men diagnosed with local or regional stage disease, a variant in AKT1, rs2494750, was also confirmed to be associated with PCSM risk (HR 0.81; p-value = 3.6 × 10-2). CONCLUSIONS: This meta-analysis confirms the association of three genetic variants with risk of PCSM, providing further evidence that genetic background plays a role in PCa-specific survival. While these variants alone are not sufficient as prognostic biomarkers, these results may provide insights into the biological pathways modulating tumour aggressiveness.

Validation of risk stratification models in acute myeloid leukemia using sequencing-based molecular profiling.

Risk stratification of acute myeloid leukemia (AML) patients needs improvement. Several AML risk classification models based on somatic mutations or gene-expression profiling have been proposed. However, systematic and independent validation of these models is required for future clinical implementation. We performed whole-transcriptome RNA-sequencing and panel-based deep DNA sequencing of 23 genes in 274 intensively treated AML patients (Clinseq-AML). We also utilized the The Cancer Genome Atlas (TCGA)-AML study (N=142) as a second validation cohort. We evaluated six previously proposed molecular-based models for AML risk stratification and two revised risk classification systems combining molecular- and clinical data. Risk groups stratified by five out of six models showed different overall survival in cytogenetic normal-AML patients in the Clinseq-AML cohort (P-value<0.05; concordance index >0.5). Risk classification systems integrating mutational or gene-expression data were found to add prognostic value to the current European Leukemia Net (ELN) risk classification. The prognostic value varied between models and across cohorts, highlighting the importance of independent validation to establish evidence of efficacy and general applicability. All but one model replicated in the Clinseq-AML cohort, indicating the potential for molecular-based AML risk models. Risk classification based on a combination of molecular and clinical data holds promise for improved AML patient stratification in the future.

MSH6 and MSH3 are rarely involved in genetic predisposition to nonpolypotic colon cancer.

A set of 90 nonpolypotic colon cancer families in which germ-line mutations of MSH2 and MLH1 had been excluded were screened for mutations in two additional DNA mismatch repair genes, MSH6 and MSH3. Kindreds fulfilling and not fulfilling the Amsterdam I criteria, showing early and late onset colorectal (and other) cancers, and having microsatellite stable and unstable tumors were included. Two partly parallel approaches were used: genetic linkage analysis (19 large families) and the protein truncation test (85, mostly smaller, families). Whereas MSH3 was not involved in any family, a large Amsterdam-positive, late-onset family showed a novel germ-line mutation in MSH6 (deletion of CT at nucleotide 3052 in exon 4). The mutation was identified through genetic linkage (multipoint lod score 2.4) and subsequent sequencing of MSH6. Furthermore, the entire MSH6 gene was sequenced exon by exon in families with frameshift mutations in the (C)8 tract in tumors, previously suggested as a predictor of MSH6 germ-line mutations; no mutations were found. We conclude that germ-line involvement of MSH6 and MSH3 is rare and that other genes are likely to account for a majority of MSH2-, MLH1-mutation negative families with nonpolypotic colon cancer.

Early age at diagnosis in families providing evidence of linkage to the hereditary prostate cancer locus (HPC1) on chromosome 1.

In a recent study of 91 families having at least three first degree relatives with prostate cancer, we reported the localization of a major susceptibility locus for prostate cancer (HPC1) to chromosome 1 [band q24; J. R. Smith et al., Science (Washington DC), 274: 1371-1373, 1996]. There was significant evidence for locus heterogeneity, with an estimate of 34% of the families being linked to this locus. In this report, we investigate the importance of age at diagnosis of prostate cancer and number of affected individuals within a family as variables in the linkage analysis of an expanded set of markers on 1q24. Under two different models for the prostate cancer locus, we find that the evidence for linkage to HPC1 is provided primarily by large (five or more members affected) families with an early average age at diagnosis. Specifically, for 40 North American families with an average age at diagnosis <65 years, the multipoint lod score is 3.96, whereas for 39 families with an older average age at diagnosis, this value is -0.84. Assuming heterogeneity, the proportion of families linked is 66% for the 14 families with the earliest average ages at diagnoses, but it decreases to 7% for the families with the latest ages at diagnoses. A similar age effect is observed in 12 Swedish pedigrees analyzed. To test the hypotheses generated by these analyses, we examined an additional group of 13 newly identified prostate cancer families. Overall, these families provided additional evidence for linkage to this region (nonparametric linkage Z = 1.91; P = 0.04 at marker D1S1660), contributed primarily by the families in this group with early age at diagnosis [nonparametric linkage Z = 2.50 (P = 0.01) at D1S422]. These results are consistent with the existence of a locus in this region that predisposes men to develop early-onset prostate cancer.

Integration of copy number and transcriptomics provides risk stratification in prostate cancer: A discovery and validation cohort study.

BACKGROUND: Understanding the heterogeneous genotypes and phenotypes of prostate cancer is fundamental to improving the way we treat this disease. As yet, there are no validated descriptions of prostate cancer subgroups derived from integrated genomics linked with clinical outcome. METHODS: In a study of 482 tumour, benign and germline samples from 259 men with primary prostate cancer, we used integrative analysis of copy number alterations (CNA) and array transcriptomics to identify genomic loci that affect expression levels of mRNA in an expression quantitative trait loci (eQTL) approach, to stratify patients into subgroups that we then associated with future clinical behaviour, and compared with either CNA or transcriptomics alone. FINDINGS: We identified five separate patient subgroups with distinct genomic alterations and expression profiles based on 100 discriminating genes in our separate discovery and validation sets of 125 and 103 men. These subgroups were able to consistently predict biochemical relapse (p = 0.0017 and p = 0.016 respectively) and were further validated in a third cohort with long-term follow-up (p = 0.027). We show the relative contributions of gene expression and copy number data on phenotype, and demonstrate the improved power gained from integrative analyses. We confirm alterations in six genes previously associated with prostate cancer (MAP3K7, MELK, RCBTB2, ELAC2, TPD52, ZBTB4), and also identify 94 genes not previously linked to prostate cancer progression that would not have been detected using either transcript or copy number data alone. We confirm a number of previously published molecular changes associated with high risk disease, including MYC amplification, and NKX3-1, RB1 and PTEN deletions, as well as over-expression of PCA3 and AMACR, and loss of MSMB in tumour tissue. A subset of the 100 genes outperforms established clinical predictors of poor prognosis (PSA, Gleason score), as well as previously published gene signatures (p = 0.0001). We further show how our molecular profiles can be used for the early detection of aggressive cases in a clinical setting, and inform treatment decisions. INTERPRETATION: For the first time in prostate cancer this study demonstrates the importance of integrated genomic analyses incorporating both benign and tumour tissue data in identifying molecular alterations leading to the generation of robust gene sets that are predictive of clinical outcome in independent patient cohorts.

Risk perception, screening practice and interest in genetic testing among unaffected men in families with hereditary prostate cancer.

Approximately 5-10% of prostate cancer cases are caused by dominantly inherited susceptibility to the disease. Although advances have been made in research concerning the genetic mechanisms of hereditary prostate cancer, little is known about the psychological consequences for men at high risk of developing the disease. The aims of the present study were to examine risk perception, interest in genetic investigations, cancer-specific worry, and screening practice among unaffected men, aged 40-72 years old, with a pedigree consistent with hereditary prostate cancer and an estimated lifetime risk of prostate cancer of 35-45%. A questionnaire was sent by mail to 120 subjects, of whom 110 responded. Most of the men (n = 90, 82%) worried about having an inherited susceptibility to prostate cancer, and 34 (31%) claimed that worry about prostate cancer affected their daily life (3 (3%) fairly much, 31 (28%) slightly). As many as 40% of the study subjects perceived their lifetime risk of prostate cancer as 67% or more. Perceived high risk was associated with symptoms of depression and with cancer worry affecting daily living. Two-thirds of the men aged 50 years old or more were regularly screened for prostate cancer. Subjects with high levels of cancer-specific stress, as measured by the avoidance subscale of the Impact of Event Scale, were less likely to opt for screening. Almost all of the men (94%) were interested in presymptomatic genetic testing (84 (76%) "definitely yes" and 20 (18%) "probably yes"). We conclude that hereditary susceptibility to prostate cancer has significant psychological consequences although it rarely causes psychiatric morbidity. The present study underlines the importance of giving thorough, repeated information to men at high risk of prostate cancer.

The objective measurement of remission and progression in metastatic breast cancer by use of serum tumour markers. European Group for Serum Tumour Markers in Breast Cancer.

An established biochemical index for monitoring therapy in patients with metastatic breast cancer was tested prospectively in a multicentre study. The index uses two serum tumour markers--carcinoembryonic antigen (CEA) and carbohydrate antigen 15-3 (CA15-3) along with erythrocyte sedimentation rate (ESR). 67 patients treated by either endocrine or chemotherapy had CA15-3, CEA and ESR measured at diagnosis of metastases and sequentially during therapy. Two markers, CA15-3 and CEA, were measured on a further 16 patients giving a total of 83 patients who were assessable for CA15-3 and CEA. Of the patients with CA15-3, CEA and ESR measured at diagnosis of metastases 84% (56/67) had elevation of 1 or more markers. During therapy the number with elevated marker(s) rose to 96% (64/67). Changes in the markers were in line with and often pre-dated therapeutic outcome as assessed by the International Union Against Cancer (UICC) criteria both for remission and progression. Patients without elevation of markers on diagnosis subsequently showed a rise in the marker(s) at or before documented disease progression by UICC. The 3 women in whom markers were at no time significantly elevated remain in remission. The results using CA15-3 and CEA were similar but 12% less patients were assessable. CA15-3 and CEA (with and without ESR) provide an objective method to guide therapy in patients with metastatic breast cancer.

Prostate cancer mortality in northern Sweden, with special reference to tumor grade and patient age.

OBJECTIVES: This study is designed to estimate the prostate cancer-specific mortality according to patient age and tumor grade in an unselected population of patients with prostate cancer who mostly received deferred or direct hormonal treatment as initial treatment. METHODS: The study population was composed of 6514 patients diagnosed with prostate cancer during 1971 to 1987 in northern Sweden. For those who died during follow-up, the cause of death was determined from the comprehensive Swedish registry data (population registries and causes of death registry). RESULTS: About 85% of these patients died during the 7 to 23 years of follow-up, and the prostate cancer-specific mortality was estimated to be 55%. Age at diagnosis was found to be a strong predictor of prostate cancer death. Patients diagnosed before the age of 60 had an 80% risk of dying of prostate cancer, whereas those over 80 years of age at diagnosis had less than a 50% risk of prostate cancer-related death. CONCLUSIONS: The prostate cancer mortality is high but decreases with older age at diagnosis. We found, using data from the causes of death registry, that the relative survival and the cause-specific survival of these patients were compatible with each other.

External radiation of the parotid glands significantly reduces drooling in patients with motor neurone disease with bulbar paresis.

The parotid glands and part of the submandibular glands were irradiated in 18 amyotrophic lateral sclerosis patients with very advanced disease and severe drooling problems. In a prospective study, a single dosage of 7.0-7.5 Gy was administered bilateral to the larger part of the parotid glands and the posterior parts of the submandibular glands. Salivary secretion rate was assayed before and after radiotherapy. Sixteen out of eighteen patients reported satisfactory to good reduction in drooling lasting up to 4-6 months, 1/18 developed xerostomia and needed saliva substitutes, and 1/18 reported no effect. Caregivers reported positive effect in all patients. The procedure was well tolerated with few side effects. Low dosage external radiotherapy of the salivary glands is effective in reducing drooling satisfactorily in ALS patients, especially in well-hydrated patients.

[Mortality due to prostatic carcinoma in northern Sweden]. / Mortalität infolge des Prostatakarzinoms in Nordschweden.

In a retrospective study 6890 patients with prostate cancer from the North Swedish Cancer Register were analyzed according to cancer specific survival. Prostate cancer mortality was 40% in patients with well differentiated cancers, 54% in patients with moderate differentiated prostate cancer and 72% in men with low differentiated prostate cancer. Prostate cancer mortality was 80% in men younger than 60 years, 63% in men 60-69 years old, 53% in men 70-79 years old and 49% in men older than 80 years.

[Gene for hereditary prostatic cancer has been located. New possibilities for early identification of men at risk]. / Gen för ärftlig prostatacancer lokaliserad. Oppnar nya möjligheter att tidigt identifiera män i riskzonen.

Prostate cancer is currently the most common malignancy among men in Sweden, and an estimated 5-10 per cent of cases are hereditary. Several epidemiological studies have shown men whose close relatives are affected to be at 2-4-fold increased risk of developing prostate cancer. In a recent genetic linkage study of 91 Swedish and North American families with hereditary prostate cancer, the first susceptibility locus, HPC 1 (hereditary prostate cancer 1), was localised at positions 1q24-25 on the long arm of chromosome 1. In Sweden, we recommend men with a strong family history of prostate cancer to undergo annual prostate-specific antigen testing and digital rectal examination from the age of 50.

N-acetyl-L-aspartyl-L-glutamate peptidase-like 2 is overexpressed in cancer and promotes a pro-migratory and pro-metastatic phenotype.

N-acetyl-L-aspartyl-L-glutamate peptidase-like 2 (NAALADL2) is a member of the glutamate carboxypeptidase II family, best characterized by prostate-specific membrane antigen (PSMA/NAALAD1). Using immunohistochemistry (IHC), we have shown overexpression of NAALADL2 in colon and prostate tumours when compared with benign tissue. In prostate cancer, NAALADL2 expression was associated with stage and Grade, as well as circulating mRNA levels of the NAALADL2 gene. Overexpression of NAALADL2 was shown to predict poor survival following radical prostatectomy. In contrast to PSMA/NAALAD1, NAALADL2 was localized at the basal cell surface where it promotes adhesion to extracellular matrix proteins. Using stable knockdown and overexpression cell lines, we have demonstrated NAALADL2-dependent changes in cell migration, invasion and colony-forming potential. Expression arrays of the knockdown and overexpression cell lines have identified nine genes that co-expressed with NAALADL2, which included membrane proteins and genes known to be androgen regulated, including the prostate cancer biomarkers AGR2 and SPON2. Androgen regulation was confirmed in a number of these genes, although NAALADL2 itself was not found to be androgen regulated. NAALADL2 was also found to regulate levels of Ser133 phosphorylated C-AMP-binding protein (CREB), a master regulator of a number of cellular processes involved in cancer development and progression. In combination, these data suggest that changes in expression of NAALADL2 can impact upon a number of pro-oncogenic pathways and processes, making it a useful biomarker for both diagnosis and prognosis.

Identification of novel CHD1-associated collaborative alterations of genomic structure and functional assessment of CHD1 in prostate cancer.

A clearer definition of the molecular determinants that drive the development and progression of prostate cancer (PCa) is urgently needed. Efforts to map recurrent somatic deletions in the tumor genome, especially homozygous deletions (HODs), have provided important positional information in the search for cancer-causing genes. Analyzing HODs in the tumors of 244 patients from two independent cohorts and 22 PCa xenografts using high-resolution single-nucleotide polymorphism arrays, herein we report the identification of CHD1, a chromatin remodeler, as one of the most frequently homozygously deleted genes in PCa, second only to PTEN in this regard. The HODs observed in CHD1, including deletions affecting only internal exons of CHD1, were found to completely extinguish the expression of mRNA of this gene in PCa xenografts. Loss of this chromatin remodeler in clinical specimens is significantly associated with an increased number of additional chromosomal deletions, both hemi- and homozygous, especially on 2q, 5q and 6q. Together with the deletions observed in HEK293 cells stably transfected with CHD1 small hairpin RNA, these data suggest a causal relationship. Downregulation of Chd1 in mouse prostate epithelial cells caused dramatic morphological changes indicative of increased invasiveness, but did not result in transformation. Indicating a new role of CHD1, these findings collectively suggest that distinct CHD1-associated alterations of genomic structure evolve during and are required for the development of PCa.